2 CYCLONE TESTING STATION SCHOOL of ENGINEERING JAMES COOK UNIVERSITY TECHNICAL REPORT NO. 54 Shoalwater and Roleystone WA tornadoes Wind damage to buildings August 2008 Authors: G. Boughton (TimberED Services, Perth) D. Falck (TimberED Services, Perth) Cyclone Testing Station, James Cook University Boughton, Geoffrey Neville (1954-) Falck, Debbie Joyce (1961-) Shoalwater and Roleystone WA tornadoes Wind damage to buildings Bibliography. ISBN Tornado 2. Buildings Natural disaster effects 3. Wind damage I. Falck, Debbie Joyce (1961-) II James Cook University. Cyclone Testing Station. III. Title. (Series : Technical Report (James Cook University. Cyclone Testing Station); no. 54). LIMITATIONS OF THE REPORT The Cyclone Testing Station (CTS) has taken all reasonable steps and due care to ensure that the information contained herein is correct at the time of publication. CTS expressly exclude all liability for loss, damage or other consequences that may result from the application of this report. This report may not be published except in full unless publication of an abstract includes a statement directing the reader to the full report

3 PREFACE Publication of this technical report continues the long standing cooperative research between the Cyclone Testing Station and TimberED. The authors Prof Boughton and Ms Falck have collaborated on other CTS damage investigations. Prof Boughton was formally a research fellow at the Cyclone Testing Station. Logistically it was far more expedient for the TimberED team to investigate the wind damage in suburban Perth than for a CTS team to travel from Townsville. The CTS is most grateful to Geoff and Debbie for preparing this report and also to the WA Department of housing and Works for supporting this work. TimberED Services Pty Ltd 3

4 Shoalwater and Roleystone WA Tornadoes Wind damage to buildings Executive Summary Outer suburbs of Perth WA experienced tornadoes from two separate events in June Both tornadoes damaged buildings and vegetation. The report provides estimates of maximum wind speeds in the tornadoes and details the damage to houses caused by these events. Although tornadoes are not covered in AS/NZS [1], the estimated wind speeds generated by the tornadoes were similar to or less than the design wind speed at roof height for all affected houses. Deficiencies in structural capacity were noted in the following details: Batten to rafter connections Rafter to top plate connections Roof structure connections Top plate to masonry connections Verandah details Particular attention to tie-down detailing is required in sheet roofs where the light weight of the roofing means that net uplift forces are higher. This investigation has also shown that some houses had been given incorrect wind classifications. Although this is usually not an issue for winds in a tornado, it would be important for other wind events. Even short duration wind events such as tornadoes generate airborne debris. Some of this debris was instrumental in causing full internal pressurization, which in turn lead to significant structural damage. In other cases, failure of doors and windows lead to full internal pressurization. Standards Australia should give consideration to amending clause in AS/NZS [1] to include buildings in all regions. 4

6 Acknowledgements The Authors are grateful to a number of people who assisted in the study. These included: The Bureau of Meteorology WA, and in particular, Joe Courtney. People of Roleystone, Shoalwater and Rockingham WA who allowed us to visit their houses and take photographs, and freely discussed their building damage with us. Department of Housing and Works WA for part funding of the work. 6

7 1. Introduction At around 7.40 am on Monday, 9 June, 2008, a tornado caused localised damage in the Shoalwater and Rockingham areas. The path of the tornado stretched for approximately 7 kms and damage was noted over the first 6 kms from the coast. At around 2.30 pm on Friday 27 th June, 2008 another tornado caused localised damage in the Roleystone area. This tornado passed over undulating terrain and its path of damage was around 2.5 km long. 1.1 Objectives This study estimates wind speeds during the event and investigates the damage to buildings in the area. The estimated wind speed is compared with the design winds for this region of Western Australia presented in AS/NZS [1] and AS4055 [2]. 2. Meteorological aspects 2.1 Shoalwater tornado 9 th June 2008 The Shoalwater tornado was embedded in a cold front. Figure 2.1 shows a satellite image of the cold front as it crossed the South West of WA. The red circle shows the locality that was affected by the tornado. The same event is shown in Figure 2.2, as a radar image, and again, the location of Shoalwater is shown by the red circle. Figure 2.1 Satellite image 09/06/08 (Bureau of Meteorology WA) 7

8 Both the Bureau of Meteorology investigation and the structural investigation covered in this report noted strong evidence in the damage of a rotating column of air. This was confirmed by eye witness accounts of the same event. There is no doubt that the damage was caused by a tornado, and the diameter of the funnel was estimated to be about 30 m. This tornado was narrow enough to affect one house and leave the houses on either side completely unscathed. Figure 2.2 Radar capture 09/06/ WST (Bureau of Meteorology WA) Figure 2.3 is a map of the tornado's path through the Shoalwater Bay area, highlighting some areas of damage. The full blue line is the path estimated by the Bureau of Meteorology and the dotted black line shows the path estimated from damage surveyed in this report. There is very little difference in the line except over Waikiki (the Eastern part of the path). In this part of the path, the estimation was based on assessment of tree damage and minor damage to roofs. The tornado travelled in a south-easterly direction, and the damage abruptly ceased at the end of the line indicating that the tornado had detached at that point. Red circles show the location of structures used to estimate wind speeds. Green circles show locations of other damaged buildings featured in the report. The dotted black line confirms that the structural damage noted by the two green circles was on the tornado path. 8

9 Figure 2.3 Shoalwater Tornado Track (Bureau of Meteorology WA) 2.2 Roleystone tornado 27 th June 2008 The Roleystone tornado was also embedded in a cold front. Figure 2.4 shows a satellite image of the cold front as it crossed the South West of WA. The red circle shows the locality that was affected by the tornado. The same event is shown in Figure 2.5, as a radar image. Figure 2.4 Satellite image 27/06/08 (Bureau of Meteorology WA) 9

11 The track of the tornado was estimated from damage to trees and houses, and was in a south-easterly direction. It is shown superimposed on a satellite photo taken from Google Earth. While many buildings sustained some damage, the green circles show some of the buildings that suffered significant roof loss. The tornado continued through bushland to the right of Figure Estimations of wind speed 3.1 Shoalwater tornado The wind speed of the Shoalwater tornado was estimated at a point early in the track as shown in Figure 2.3. The maximum wind speed is reported as an estimated velocity at roof height at the site. The estimate draws inferences from damage to two structures and vegetation. There are errors in these inferences that are related to the complexity of the structure and other factors. The reliability is moderate and estimates are likely to be within +/- 15% Wind speeds estimated from damage to a sheet roof Wind speeds at roof height were estimated at between 110 and 120 km/h or 32 to 34 m/s. This building was less than three years old and had sustained considerable damage including: Damage to front door fixings that meant the front door blew in as the strong winds first arrived. Loss of part of the roofing near a hip (roofing had battens attached). Partial separation of part of the roof structure from the walls including lifting of some bricks to which the top plate had been fastened. Partial separation of batten to rafter connections throughout the roof. Partial separation of some underpurlins from struts and some struts from strutting beams. Maximum wind direction Lifted roof Figure 3.1 External (front) view of sheet roof house 11

12 This damage will be examined in more detail in section 4. The lower bound wind speed was estimated from the relatively simple structural system of roofing tied to battens which separated from the rafters. The failure required failure of approximately 30 nails at the batten to rafter connections, so the average nail withdrawal load could be used to estimate the resistance. The pressure coefficients were taken from wind tunnel studies on hip roofs reported by Xu and Reardon [3]. The upper bound wind speed was estimated from the weight of the whole roof together with roof anchorage around the perimeter offered by skew nails at each rafter / top plate connection. Again average wind pressure coefficients were estimated for each hip roof surface from Xu and Reardon [3]. While the whole roof had lifted around 25 mm, it had not actually separated from the walls. It was estimated that the actual roof height wind speed was close to the upper bound. Figure 3.1 shows a general view of the house viewed at 90 degrees to the direction of peak winds. There is no debris damage in this view, but the lifted roof is obvious by the gap over one column and the movement on the other. While the roof has moved, it did not become detached as a whole Wind speeds estimated from damage to a tiled roof Wind speeds at roof height were estimated at between 110 and 160 km/h or 32 to 43 m/s. This recently completed building was located within 150 m of the one detailed in Section and with the same relative positioning to the tornado track. This building had sustained damage to the roof including: Loss of some tiles near the hips. Subsequent collapse of ceiling due to water ingress. Figure 3.2 shows a general view of the house showing damage to roof tiles near hips. Maximum wind direction Missing tiles Missing tiles Figure 3.2 Damage to tiled roof due to wind loads 12

13 This damage will be examined in more detail in section 4. The lower bound wind speed was estimated from the relatively simple structural system of individual tiles. There were no signs of debris damage to this house. The pressure coefficients were taken from peak pressures in wind tunnel studies on hip roofs reported by Xu and Reardon [3]. The upper bound wind speed was estimated from the weight of the whole roof. Again average wind pressure coefficients were estimated for each hip roof surface from Xu and Reardon [3]. There was no indication that the roof had lifted from the wall structure. It would not have mobilized anchorage/ tiedown forces in roof to wall connections. 3.2 Roleystone tornado Observations of damage to vegetation indicated that the wind speeds in the Roleystone tornado seemed vary more over the distance travelled than those in the Shoalwater tornado. The vegetation damage was light over the first half of the track shown in Figure 2.6 and much more significant in the second half of the track. It was very difficult to obtain actual estimates of the wind speed, however the following conclusions about the relative speed of the event could be drawn from the damage to trees. Figure 3.3 shows damage to trees in this event: In the first half of its path, the Roleystone tornado had a lower wind speed than the Shoalwater tornado. Here only branches less than 100 mm were broken and leaves remained on most trees in its path. Some deciduous trees even retained some autumn leaves. In the second half of its path, the Roleystone tornado had a higher wind speed than the Shoalwater tornado, but there were no buildings that were in the direct path of the tornado in this half. There were a number of buildings that were close to its path and some of these were damaged. An estimate of the wind speed in the wall of the tornado was 180 to 200 kph as some trees in excess of 400 mm diameter had been broken half way up the trunk. (a) Damage in first half of path (b) damage in second half of path Figure 3.3 Damage to trees in Roleystone tornado 13

14 3.3 Wind speeds compared with design wind speeds Shoalwater tornado The range of wind speeds estimated in the Shoalwater tornado for both houses was similar. The best estimate indicated in Section 3.1 is 120 km/h (34 m/s) at roof height, which is close to the design wind speeds at roof height for a single storey house in flat suburban terrain in Region A given in AS/NZS [1] and AS4055 [2]. (In AS4055 [2], the ultimate limit state wind speed for an N1 house is 34 m/s and for N2, 40 m/s.) This estimate of wind speed is compatible with damage to trees which unless damaged by flying debris was restricted to broken branches and uprooting of very shallow rooted species. The event could be classified as an F1 tornado according to the Fujita scale for tornado wind speeds as indicated in Table 3.1 [4]. Table 3.1 Fujita Scale for measuring Tornado intensity (Bureau of Meteorology) F number Wind Speed Damage F kph Some chimneys damaged, twigs and branches broken off trees, shallow-rooted trees pushed over, signboards damages, some windows broken F kph Surface of roofs peeled off, mobile homes pushed off foundations or overturned, outbuildings demolished, moving autos pushed off the roads, trees snapped or broken; F kph Roofs torn off frame houses, mobile homes demolished, frame houses with weak foundations lifted and moved, large trees snapped or uprooted, light-object missiles generated F kph Roofs and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted, heavy cars lifted off the ground and thrown, weak pavement blown off the roads F kph Well-constructed houses leveled, structures with weak foundations blown off the distance, cars thrown and disintegrated, trees in forest uprooted and carried some distance away F kph Strong frame houses lifted off foundations and carried considerable distance to disintegrate, automobilesized missiles fly through the air in excess of 300 feet, trees debarked, incredible phenomena will occur Figure 2.3 shows that the buildings used to estimate the wind speed in the event were in the region with the maximum damage and quite early in the track of the Shoalwater tornado. Damage levels to buildings and trees alike were much lower for the last one third of this tornado, and no structural damage was observed for the last kilometre of its track. 14

15 The maximum intensity of the Shoalwater tornado appeared to be F1, and it is likely that it was F0 for the last two or three kilometres of its track Roleystone tornado The first half of the Roleystone tornado passed over a large number of houses, and in this half, the wind speeds were estimated to be less than the wind speeds in the Shoalwater tornado. The tornado was likely an F0 event for this portion of its path. In the second half of the Roleystone tornado, after the path had crossed a forested ridge, the intensity appeared to increase to a high F1 or low F2. There were no houses in the direct path of the tornado in this region, but some just outside the path were significantly affected. The wind speeds at those locations were difficult to estimate Wind speed at houses compared with design wind speed The Scope of AS/NZS [1] excludes its use for determining wind speeds and resulting wind actions caused by tornadoes. This is because of the following uncertainties in tornado wind actions: Both the variation of wind speed with height and turbulence intensity are not known for tornadoes, so the M z,cat term used to establish gust wind speed at the structure from the regional wind speed cannot be evaluated. Pressure fields in the tornado itself may complicate the differential pressures across building surfaces evaluated using AS/NZS [1]. However, in this report, estimations of wind speed caused by the tornado at the building height can be compared directly with the wind speeds for which the buildings should have been designed. The maximum tornado wind speeds at the building height. This can be directly compared with structure height design wind speeds which have been derived from 10 m height regional wind speeds with M z,cat correction for building height and turbulence intensity. The maximum wind speed at roof height from the tornado can be directly compared with the design gust wind speed at the same height. The basis for the comparison is the same. The concern about very low tornado central pressures is that once a tornado envelopes a building there is a differential across the surface caused by the central pressure of the tornado that makes the building "explode". If this is the case, then damage may not be due to wind pressure, but the sudden pressure drop as the tornado passes. For this study, the damage was associated with door or window failure on a windward wall in which the glass or door was blown inward. This mode of failure could only have occurred under the action of wind pressures not localised low tornado pressures. For these reasons, it is valid to use the wind speeds that caused the damage to predict the type of damage that would occur had the same wind speeds resulted from winds that were within the scope of the Australian Standards [1], [2]. Therefore, the design wind speeds for houses throughout the tornado tracks in this report were calculated using AS/NZS [1] and AS4055 [2]. The entire path of 15

16 the Shoalwater tornado was across flat topography and all but the start of the path, the terrain category would have been classed as Terrain Category 3. The shielding varies, but in the recent housing, it was sparse enough to be regarded as partial shielding. For only a small part of its track, could the housing be regarded as fully shielded. The entire path is in wind region A. The design wind speed of 34 m/s given in AS4055 [2] is the ultimate wind speed for N1 housing corresponding to the design conditions outlined above. The design wind speed of 33 m/s given in AS/NZS [1] is the ultimate (500 year return period) wind speed for 3 metre high buildings designed for the conditions outlined above including partial shielding. The estimated peak wind speed in the tornado was very close to the design wind velocity for all of the modern housing in its path. The path of the tornado in Roleystone passed over undulating topography. Many of the houses had topography class T2 and partial shielding. This put them into wind classification N2 and N3. Their construction details should have been matched to wind speeds of 40 m/s or 50 m/s, well in excess of the wind speeds in the first half of the tornado. (In the first half of the Roleystone tornado, the wind speed was estimated to be significantly less than 34 m/s.) Hence, even houses in N1 locations on this path should not have experienced winds near their design wind speed, 34 m/s. 16

17 4. Damage to buildings The damage indicated that the tornado had a width of around 30 m. It was estimated that over the 7 km of the track that it affected over 200 houses, and the State Emergency Service responded to around 250 calls from the suburbs that included the tornado path. Even though some of these may have been to deal with fallen trees, the figure is large enough to indicate that there were more houses affected by the tornado than those that were in its direct path. The SES also reported that around 15 houses had been 'unroofed', though this statistic may include a number that had lost less than half of the roof or roofing. The roof damage observed was commensurate with wind pressures and suctions from high speed wind. The study did not attempt to examine each damaged building, but sought to examine in some detail damage that was seen as quite typical. 4.1 Wind damage to modern tiled roofs Wind direction Tile trajectories (a) tiled roof with wind damage (b) tile with nail in place on the ground Figure 4.1 Wind damage to tiled roof 17

18 A number of tiled roofs suffered some damage. In the Perth metropolitan area, standard practice is to nail down every second tile, and every attempt is made to stagger the pattern at each row. Each tile that is not anchored has an anchored tile on either side of it, and in most cases, an anchored tile above and below it. In a few cases, the damage could be entirely attributed to wind pressures alone. In most cases, the damage was associated with debris impact on the tiles. Figure 4.1 shows a roof with incidental tile damage in areas of the roof that would have experienced very high suctions under wind actions alone. In the affected area, there was no sign of debris impact and many of the tiles had been removed with little breakage. In some cases, the nail used to anchor the tile was still in place in the tile. The tiled roof used for wind speed estimation and illustrated in Figure 3.2 also experienced wind damage to tiles. In all of these cases, relatively small areas of roof were affected by the tile damage. It was only parts of the roof close to the intersections of roof planes (hips and ridges) that were subjected to tile loss. This indicates that at the design load, the highest loaded regions of the roof are close to their capacity. Figure 4.2 shows a roof panel that experienced particularly high suctions, and it can be seen that while the tiles just below the ridge are still intact, they have almost lifted off. The tiles near the hip have been lifted by the wind. Tiles at hip rafter lifted off Tiles below ridge lifted but still attached Figure 4.2 tiles in high uplift regions of the roof. The estimated tornado wind speed was sufficient to lift individual tiles under external suctions. As the estimated tornado wind speed was close to the design wind speed for this location, the design wind speed is also sufficient to lift individual unfastened tiles. In peak suction areas of hip roofs, uplift forces exceed the weight of the tile at gust wind speeds of between 25 and 30 m/s. 18

19 4.2 Wind damage to sheet roofs Most of the more conspicuous damage along the path of the tornado involved damage to sheet roofs. All of the roofs we observed that had damage to more than 50% of the roof were sheet roofs Modern stick-built roofs Some damage typical of "stick-built" roofs (roof framing using rafters and underpurlins instead of trusses) with sheet roofing that were in the direct path of the tornado is explored in Figures 4.3 to Figure 4.5. Figure 4.3 shows a view of the roof from inside the house. The most obvious problems are that the roof has lifted over the room from which the photo was taken, and the ceiling has collapsed with the subsequent water damage. However, a more detailed investigation inside the roof showed that many of the structural connections in the roof had been significantly compromised and the whole roof structure was very close to a comprehensive failure. Figures 4.4 and 4.5 were taken from inside the roof space in an area in which the roof sheeting was still attached, and where from an external perspective, there were no problems. Loss of roofing, with some battens attached see Figure 4.4(a) Nail top plate to brickwork Separation of rafter to wall plate connection Strap for anchorage of top plate to brickwork Lifting of wall plate see Figure 4.4(b) Figure 4.3 Wind uplift damage to sheet roof Figure 4.4 (a) shows a batten to rafter connection in which three gun driven nails had been used. In other parts of the roof, only two nails were used. However, where the roof had detached, battens and the roof sheeting remained together. The batten to rafter connection was a weakness in the outer roof structure. In some places on this house, rafters had also separated from the wall plates. 19

20 (a) batten to rafter connection (b) rafter to top plate connection Figure 4.4 Separation of connections in the outer roof structure (a) connection at top of strut (c) connection at hip rafter (b) connection at bottom of strut Figure 4.5 Separation of connections in the inner roof structure 20

21 The anchorage of the rafters at the eaves consisted of skew nailing to the top plate as shown in Figure 4.4 (b), and the top wall plates were tied to the brickwork with nails through the top plate into the brickwork and straps over the top of the top plate. The top plate to wall connection details are shown in Figure 4.3. In this house only 25% of the roof was lost due to failure of 2 nail batten to rafter connections. However, elsewhere in the house, where the roof remained attached to the roof structure, there was significant distress to the connections between underpurlins, struts and strutting beams. Figure 4.5 shows the movement opened up at these joints in spite of the use of a large number of skew nails. In the strutting system, roof carpenters can appreciate the load path when the roof is loaded with gravity loads, but do not provide tie down through the same load path for uplift loads. With lightweight roof systems, wind uplift can be significantly more than the dead weight of the structure. AS [5] has details for anchorage of underpurlins and struts under wind loads (AS [5] Table 9.23). These details were not seen on any stick-built roofs in this study. (a) Upper storey with loss of most of roof structure (b) Detail where parts of structure remained Figure 4.6 Loss of roof structure from second storey 21

22 Figure 4.6 shows another stick-built roof in which almost the entire structure was lost. The house was under construction at the time In this case, the rafter to top plate connections had failed, and the tie down from the struts was ineffective as well. Most of the struts had been lost with the house. In many rooms, the ceiling structure remained intact, but water damage to the plasterboard meant that it had fallen in. Figure 4.6(b) shows enough detail of the structure remaining to identify it as a stickbuilt roof. Throughout the second storey, the top plate had lifted from the brickwork, but over much of the house, the weight of the ceiling and the action of the strap had kept it attached. However, the rest of the roof structure had largely been lost. This included lifting of the rafters at the eaves and struts in the central part of the roof. Over much of the roof, the struts, underpurlins and rafters were missing with the roof debris. This house was nearing completion at the time of the tornado. All of the external construction had been completed, the internal walls and ceilings plastered, and fit out was near the end. All roofing, trims and flashings were fitted. The roof debris which was in one large piece cleared another two storey house and covered over 150 m before landing in public open space. There was no sign of prescribed AS [5] tie downs on struts in this house. The red circle in Figure 4.6(b) shows the top of a strut where the underpurlin has been lifted off the strut. Figure 4.7 Loss of roof structure two storey house Figure 4.7 shows another house of recent construction in which most of the roof structure had lifted. Again, sufficient timber was left to be able to identify the construction as stick-built. On the little part of the roof structure remaining, the batten to rafter connection had failed. 22

23 The majority of the roof had lost all of the roof structure above the ceiling joists and top plate. Again, struts and underpurlins had all been lost with the rest of the roof structure. The houses illustrated in Figures 4.6 and 4.7 were both two storey houses. AS4055 [2] assigns the same wind category to single and two storey houses, and in Terrain Category 2 or 3, the design wind speed derived from AS/NZS [1] is the same. It is unlikely that there is a difference between wind speeds at 3 m and 6 m during tornadoes, as the wind in tornadoes does not usually travel a sufficient distance over land to develop a boundary layer. Therefore, the winds experienced in this event for these two houses would also have been close to the design wind speed. In light weight (sheet) roofs, uplift forces exceed the weight of the roof at or below the design wind speed. Tie down of all structural elements in the roof is essential. A range of appropriate details of tie down connections in stick-built roofs is given in AS [5]. However, there was little evidence of them being used in the badly damaged buildings in these events Modern trussed roofs A number of sheet roofed houses that were substantially damaged had trussed roofs. Figure 4.8 shows one in which the roofing and battens have lifted. (a) roof batten loss (b) lifting of timber top plate at truss heel joint Figure 4.8 wind uplift on trussed roof 23

Produced in conjunction with: qbcc queensland building and construction commission Bracing, tie-down and other issues A guide to the construction of buildings in cyclonic regions 1 AS 1684 is:- A recipe

Repair of sheet metal roofs in cyclonic areas Guideline - February 2015 Contents Contents...2 1. Introduction...3 Building approvals...3 What is a building approval?...3 Is a building approval required

CYCLONES. IS YOUR HOUSE READY? A Homeowner s Guiide THIS GUIDE WAS PREPARED BY THE CYCLONE TESTING STATION WITH SUPPORT FROM NORTHERN TERRITORY, QUEENSLAND AND WESTERN AUSTRALIAN GOVERNMENTS 1.. INTRODUCTION

Queensland Reconstruction Authority Planning for a stronger, more resilient North Queensland Part 2 Wind resistant housing Queensland Reconstruction Authority Planning for a stronger, more resilient North

Chapter 9 STRUCTURAL CONCEPT FOR LIGHT GAUGE STEEL FRAME SYSTEM 9.1 BACKGROUND Steel is widely used in the construction of multi-storey buildings. However, steel construction is seldom used and is traditionally

Legend Insulation zone Blue text Air tightness barrier (note: this can also act as a vapour control layer) Guidance on thermal continuity Red text Guidance on air tightness Values used in psi calculations

Good Craftsmanship Guide Carpentry and Joinery- Carcassing Introduction This Good Craftsmanship Guide highlights key problems with the major elements of Carpentry and Joinery - Carcassing, and gives guidance

T H E W I N D Protecting Your Home From Hurricane Wind Damage During a hurricane, homes may be damaged or destroyed by high winds and high waves. Debris can break windows and doors, allowing high winds

TRAINING OUTLINE FOR PART TIME BUILDERS This is a training outline for persons who get involved in repair work and minor building work, emphasizing disaster resistance and good practice. It is intended

Legend Insulation zone Blue text Red text Air tightness barrier (note: this can also act as a vapour control layer) Guidance on thermal continuity Guidance on air tightness Values used in psi calculations

Glossary of Roof Truss Technical Terms (with thanks to Wolf Systems Ltd) A APEX/PEAK The uppermost point of a TRUSS. ASYMMETRIC TRUSS A truss with two rafters meeting at the APEX, having a different pitch

2400 x 3000 (8ft x 10ft) Storage Shed Plans Page 1: Introduction and Contents This detailed shed plan-set is in both Standard and metric dimensions. It is built on skids, meaning that there are no footings

POST AND FRAME STRUCTURES (Pole Barns) Post and frame structures. The following requirements serve as minimum standards for post and frame structures within all of the following structural limitations:

Add Strength and Water Resistance When Repairing Your Walls Any home repair or remodeling work you do presents an opportunity to make your home fare better in the next storm. Whether you are just replacing

Ventilation 53 Building Construction The firefighter s ability to safely and efficiently ventilate a building through its roof will depend to some degree on the firefighter s understanding of roof construction.

March 14, 2007 Re: Installation of Bay, Bow and Garden Windows Attached are the Atrium Companies, Inc recommendation for the installation of bay, bow and garden windows. These instructions were developed

Timber Decks Technical Note. March 2007 This Technical Note contains general information for residential timber decks and floor frame structures for veranda s, patios etc which are exposed to the weather.

Protecting Roofing Systems Against Windstorm Damage This brochure is made available for informational purposes only in support of the insurance relationship between FM Global and its clients. This information

December 2007 GANG-NAIL FLITCH BEAM Manual GANG-NAIL FLITCH BEAMS are available only through GANG-NAIL Fabricators throughout New Zealand Refer to the MiTek New Zealand website for up to date GANG-NAIL

How to Use this Guide Provide two sets of plans, drawn to scale and complete the following (hint: use graph paper with 1/4" squares. Example: 1/4" =1'): Check with your jurisdiction for additional requirements.

CARPENTRY & JOINERY FCA CARPENTRY & JOINERY THEORY 10 SIMPLE ROOF Double Roofs A double roof is a roof whose rafters are of such a length that they require an intermediate support. This support is usually

Structural Criteria for Residential Rooftop Solar Energy Installations Use of this document This toolkit document includes a one-page list of structural criteria for over-the-counter or online approval,

Protecting Your Home from Wind Damage During severe thunderstorms or hurricanes, homes may be damaged or destroyed by high winds. Debris flying through the air can break windows and doors, allowing high

TIMBER CONSTRUCTION Chris Arnold, Building Systems Development, USA BACKGROUND Wood construction is common for many single-family houses throughout the world. In areas where timber and wood materials are

Practice te 2016-32 When is a Building Permit Required? This updates the previous Practice te 2014-32 issued May 2014 1. SUMMARY A Building permit is required for most building work, however some building

4.3.5 - Breakaway Walls Elevation of a structure on a properly designed foundation reduces the potential for water damage from flooding. When the space below the lowest elevated floor is maintained free

Assessing Structural Damages Please note-this presentation is only intended to be used as a basic educational tool and is by no means all encompassing. Each property should be treated on a case by case

CARPENTRY - HOUSING HIP and VALLEY ROOFING The text provides subject matter related to more detailed hip and valley roofs. It builds on knowledge and skills acquired during basic roof framing. There are

une 2008 GANG-NAIL ROOF TRUSS SYSTEM (incorporating Attic Trusses) Residential Manual GANG-NAIL Roof Truss Systems are available only through GANG-NAIL Fabricators throughout New Zealand Refer to the MiTek

Severe Weather Tornado Tornado A tornado (aka twister) is a violently rotating column of air (wind vortex) that is in contact with both the Earth surface and a cumulonimbus cloud or, in rare cases, the

Overview: 1971 N 1966 GYM 1966 CLASSROOM WING 1966 AUD. 1971 GYM 1998 1998 POOL EAST LYME HIGH SCHOOL Original 1966 Building: The original East Lyme High School was constructed in 1966 and was composed

Conservatory Roof Structural Information Guide Effective from ugust 8 Useful Information This guide displays data on the permissible roof member spans and for different roof loadings; it should be used

210108 fire separating walls #2 ISSUE BSA has identified a number of instances of defective fire separating walls in duplexes, town houses and multi-residential complexes. The system of fire separating

COMMON FRAMING PROBLEMS AND HOW TO AVOID THEM Wood-frame homes continue to be the dominant choice for both home buyers and home builders in the U.S. Tens of millions of homes have been constructed with

Chapter 3: Roof Tutorial The majority of Roof Tutorial describes some common roof styles that can be created using settings in the Wall Specification dialog and can be completed independent of the other

Juneau Permit Center, 4 th Floor Marine View Center, (907)586-0770 This handout is designed to help you build your deck to comply with the 2006 International Residential Building code as modified by the

CARPENTRY - HOUSING PART 2: GABLE ROOFS The gable roof is classified as being double-pitched and one of the simplest roof forms, due to the fact that all rafters in the roof are exactly the same length

Forms play a major role in concrete construction. They give the plastic concrete its shape and hold it until it hardens. Forms protect the concrete, assist in curing it, and support any reinforcing rods

Juno Beach Building Department Mitigation Retrofits Guidelines Roof Decking Attachments & Secondary Barrier Through research, testing and the analysis of the real life structural damage due to high winds,

CHAPTER 5 Elevating Your House Introduction One of the most common retrofitting methods is elevating a house to a required or desired Flood Protection Elevation (FPE). When a house is properly elevated,

Protecting YOUR NEW HOME FROM Wind Damage Blueprint for Safety... A Blueprint for Life When severe weather threatens, protecting life and property automatically becomes top priority for millions of Florida

2012 Edition High Wind & Hail Standards FORTIFIED is a program of the Insurance Institute for Business & Home Safety Table of Contents Program Overview and Definitions 5 Goals 5 Objectives 6 Designation